This invention relates to a rotary joint used for sealing and joint rotation and, more particularly to a rotary joint used in armored diving suits and which joint includes fail-safe sealing.
Joints used in armored diving suits are, of course, well known in the industry. Such joints have typically used a fluid within the joint which fluid is held in a cavity defined by seals and such a joint is illustrated and described in U.S. Pat. No. 1,414,174 (Compos). Compos teaches that portions of the rotary joint contact the fluid and the fluid prevents the joint from collapsing under the high operating pressures under which such diving suits are typically used. The fluid, being practically incompressible, acts to support the joint members with which it is in contact and further acts as a lubricant to offer a substantially friction free or very low friction support surface for rotary motion of the members of the joint in contact with the fluid.
However, problems are inherent with existing apparatuses used for sealing the suit and allowing rotary motion of the joint. One problem is that tilting or misalignment often occurs between joint members about the axis of rotation. Such tilting or asymmetric configuration of the members may result in seals otherwise concentric about the axis of the joint being lifted out of contact with their complementary sealing members on one side of the joint. Such asymmetry of the seals can cause leakage from within the annular cavity of the rotary joint. Such leakage is to be prevented since, of course, the water within which the diver may be operating may enter the internal cavities of the suit. This leads to a situation which is to be avoided.
U.S. Pat. No. 4,459,753 (Nuytten) teaches a rotary joint in which circumferential rings maintain concentricity of the joint about a vertical axis. Nuytten, however, does not prevent tilting or misalignment of the upper ring with respect to the rotating seals and if the aforementioned side loads about the axis of rotation arise, the upper and lower joint elements may tilt. This asymmetry tends to lift or displace one edge of the seal off the mating surface which can cause the aforementioned problem where fluid tends to leak and wherein the joint collapses. This is a further situation to be avoided.
U.S. Pat. No. 4,903,941 (Nuytten) teaches a similar rotary joint where the upper and middle members are aligned by means of balls or a TEFLON (Trademark) strip. In the joints taught by both of these patents, the adjacent joint elements are aligned radially but are free to move axially. However, since two adjacent joint elements must be accurately aligned both axially and radially, Nuytten ""032 suffers from the possibility of such misalignment.
According to one aspect of the invention, there is provided a rotary joint for a diving suit comprising first and second members having a sealing relationship therebetween defining a fluid holding cavity, said rotary joint comprising at least one seal between said first and second members extending about an axis and a tilt prevention member operably located between said first and second members to allow relative rotation of said first and second members and to prevent axial relative movement between said first and second members said at least one seal including a seal mounted for axial movement within one of said first and second members.
According to yet a further aspect of the invention, there is provided a fail-safe sealing arrangement for a diving suit having an internal opening for a user, said fail-safe sealing arrangement comprising first, second and third members defining a first sealed fluid carrying cavity sealed by a first set of seals and a second sealed fluid carrying barrier sealed by a second set of seals, said second set of seals being operable only upon sealing failure of said first set of seals.
According to still yet a further aspect of the invention, there is provided a fail-safe sealing arrangement for a diving suit having an internal opening for a user, said fail-safe sealing arrangement comprising first, second, third and fourth members defining a first sealed fluid carrying cavity sealed by a first set of seals and a second sealed fluid barrier sealed by a second set of seals, said third and fourth members being axially movable relative to said first and second members and said second set of seals being operable only upon failure of said first set of seals and when said first and third members are in contacting relationship preventing further relative axial movement therebetween.